Until now, the big Tory theme was that Britain was broke. Not the "Broken Britain" stuff, but broke as in bankrupt: facing such a large public finance deficit that there is a real chance that investors will stop lending us money.

Upon this perfectly logical premise was built not just the Tory critique of Labour, but also its own "tough love" prescription for the future. Public spending would need to be cut harder and faster than the other parties dared admit, in order to bring the deficit under control and avoid a far worse fate.

Only that wasn't much of a political manifesto. It seems to have been slowly dawning on the Conservative faithful that this austere campaigning style could backfire badly, depriving them of a majority, or worse.

In the long run, the new message is perfectly consistent with Tory principles and values. Unlike Osborne's previous crowd-pleaser on inheritance tax, it even helps low earners most. And the shadow chancellor claims to have identified further public spending "efficiencies" to pay for it without hitting frontline services.

Yet, like with most "money off" offers, there is a catch: it comes at the price of fatally undermining Osborne's earlier analysis of "broke Britain". Public-sector efficiency savings in the low single billions cannot possibly account for the difference in the two messages. Either Osborne was right that Britain's colossal deficit threatens to wreck the economy, in which case this is a reckless piece of political grandstanding. Or perhaps he is right now that there is enough wiggle-room to give voters some money, in which case what was all that stuff about economic armageddon?

It may prove an inspired gamble that energises the Tory base with a simple offer that cuts straight through to the ballot box. Or it may be a panic response to narrowing polls by an inexperienced team looking to pep up their manifesto. What it ain't is internally consistent.